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Lake Pontchartrain Causeway - Exploring the "World's Longest Bridge"


One of the great engineering achievements of southeast Louisiana – a region of the country that is no stranger to impressive feats of engineering – is the Lake Pontchartrain Causeway, or “The Causeway” as its often referred to, spanning the Lake between suburban Jefferson Parish outside New Orleans and the north shore community of Mandeville. At a length of 23.9 miles from end to end, it is one of the longest bridges in the world – long enough to be classified in the Guinness Book of World Records as the “longest continuous bridge over water in the world” as of January 2024.

The idea for the modern Causeway was conceived in the years after World War II, when the New Orleans metro area grew quickly as the suburban development of Jefferson Parish threatened to spill over into the neighboring parishes. The Greater New Orleans Expressway Commission (also known as the Causeway Commission) was established in 1948 with the goal of planning and constructing the cross-lake bridge. Construction of the initial two-lane bridge took place from 1953-1956 at a cost of $46 million, including improvements to Causeway Boulevard in Metairie and Mandeville.

The above satellite view shows the greater New Orleans metro area to the bottom of the photo. Lake Pontchartrain, and the Causeway that crosses it, are visible at the center.

The Causeway proved to be a huge success from the beginning. In fact, in some ways it became a victim of its own success, with traffic counts soon proving to be too great for the two-lane bridge to safely handle. In response, planning for the parallel span took place in the early 1960s, with the new span opening in 1969 at a cost of $30 million. Since the completion of the parallel span, southbound traffic crosses on the original bridge, while northbound traffic crosses on the second bridge. While lying mostly level with the lake for its entirety, there are multiple raised navigation spans along the way for taller recreational boating traffic to pass safely under the bridges. A high-level bascule draw span stands near Milepost 17, about 8 miles south of the Mandeville shoreline, enabling larger commercial craft to pass the bridge. (On the Causeway, the mileposts begin with "0" located at the Metairie shoreline.)

These photos from November 2023 are taken from the Metairie shoreline and show how the Causeway starts out over the lake and disappears over the horizon. (Click on each photo to view a larger version.)

The Causeway is operated as a toll bridge. As of January 2024, the cost is $6 for passenger cars, collected in the southbound direction at a toll plaza on the Mandeville approach to the bridge. Tolls were originally collected in both directions, however northbound toll collection ceased in 1999 and the original northbound toll plaza located at the end of Causeway Boulevard in Metairie was removed. The frequent traffic jams caused by the toll plaza that often spilled over onto Causeway Boulevard and the nearby intersection thoroughfares played a role in this decision. In any case, the Causeway is one of the only tolled facilities in the state of Louisiana. The tolls provide revenue that helps maintain the bridges as well as fund improvement projects. The most significant of these took place in 2019, when a $53 project saw the addition of emergency pull off areas to the bridge in both directions. A separate project carried out later that year saw the replacement and improvement of the railings and parapet barriers along the length of the southbound bridge. All the measures taken lately have significantly improved safety along the Causeway as traffic counts are now as high as they have ever been.

The immense proportions of the Causeway's length can be appreciated the most from the air. These 2017 photos of the Causeway were taken by yours truly as an airplane passenger above Lake Pontchartrain. (Click on each photo to view a larger version.)

I’ve had the opportunity to drive the Causeway on multiple occasions over the years. My first visit to the crossing came in January 2017 as part of my initial visit to southeast Louisiana. In February 2023, I revisited the Causeway and got to experience a round-trip crossing on the bridge a second time. Crossing this bridge is one of those unique experiences that is both enjoyable and unpredictable at the same time. At a point about 10 miles into the crossing, land in all directions disappears from sight and one has the feeling of being isolated from civilization for a period of time. In the southbound direction, it’s often the case that the first signs of land to appear on the horizon are the skyscrapers of downtown New Orleans off to the southeast (including the roof of the Superdome) and the looming structure of the Lakeway Center located on Causeway Boulevard directly ahead.

Above: The skyline of New Orleans comes into view about 15 miles to the southeast as one travels southbound on the Causeway.

At a length of 24 miles from end to end, it’s one of the longest stretches of highway in America without any interchanges or ways to divert to an alternate route in the event of trouble. Weather conditions often change rapidly over the lake, meaning that the conditions that one encounters when setting off on the Causeway can sometimes be very different only a few miles later. In the winter months, dense fog is not uncommon over parts of the lake, meaning the visibility can drop rather abruptly with little warning. In the summer months, the trademark Louisiana thunderstorms can form quickly over the lake and drift over the Causeway, causing hazardous conditions on a moment’s notice. The variable weather conditions that can be experienced on any given day, plus the typical risks for vehicle-related incidents on a bridge of this length, combine to make for an exciting trip that always requires driver attention due to potential unforeseen factors.

The following images from February 2023 chronicle the crossing of the Causeway northbound, from Metairie to Mandeville. Click on each photo to see a larger version.

The following images from February 2023 chronicle the crossing of the Causeway southbound, from Mandeville to Metairie. Click on each photo to see a larger version.

Dashcam video of the northbound drive over the Causeway was filmed in February 2023 for the 'roadwaywiz' YouTube channel and is available for viewing at the link below:

Dashcam video of the southbound drive over the Causeway was filmed in February 2023 for the 'roadwaywiz' YouTube channel and is available for viewing at the link below:

How To Get There:

Bridges, Crossings, and Structures of the Lower Mississippi River
Visit the Bridges of the Lower Mississippi River Home Page


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